My truck would sometimes idle at 1500 rpm for no reason. It would also sometimes surge/buck/fart at low speed cruise. Sometimes a re-start would fix it. Sometimes a quick rev in neutral would fix it. It seemed to be returning more frequently, and getting worse.

The Snap-On MODIS at work suggests ripping into the wiring harness, near the back of the valve cover near the firewall. It says there is a crimp connection in there that runs the injectors. The connection may ~look~ good, but cut it apart and resolder it. So I did.

FIX:

Remove the air filter.* This connection was previously "tweaked" by me with a couple zap straps.* That's the bundle I'm going into.

Unsheath everything.* You will find two connections taped up.* I opened up both.

There five white wires are crimped together near the top.* Below them, you can see some green wires crimped together.

I cut the connection out, and wrapped the wires all together after sliding some heat-shrink tubing up and out of the way (not shown).

Then soldered.

Then heat-shrink tubing.

The white wires are next - vice-grips holding the heat-shrink tubing out of the way.

And heat-shrunk.

And then re-wrapped.

Here's what the wires actually do:

RESULT: Smoother idle, no return of the weird cruise issues or 1500 rpm idle. Cold-start fast-idle works much happier.